Smokey 1994 explorer with no codes...

[tkarman]

Hello! Great forum! I've got a 1994 Explorer that had codes 157 and 332 and was blowing nasty black smoke out when I pumped the gas. With the help of this forum's info I replaced the MAF and DPFE. Now the codes are gone, car is idling much better and the black smoke has been reduced to brown smoke. Still running rich I beleive? I am going to change the O2 sensor and the Coolant Temperature Sensor next...but I want to make sure this is a good idea first. Would either of these send a code if they were failing? Or is this just a good idea anyway since the car has 170,000 miles.

 

[JDraper]

Welcome to the forums! I'd check the fuel pressure regulator too. If that goes bad, it won't necessarily throw a code, but it will make the motor run very rich. Easiest way to test it is to pull the vacuum hose off and see if there is fuel present. If there is fuel present, the fpr is bad.

A bad 02 sensor would definitely throw a code. I don't think a bad coolant temperature sensor would though.

 

[tkarman]

Welcome to the forums! I'd check the fuel pressure regulator too. If that goes bad, it won't necessarily throw a code, but it will make the motor run very rich. Easiest way to test it is to pull the vacuum hose off and see if there is fuel present. If there is fuel present, the fpr is bad.

A bad 02 sensor would definitely throw a code. I don't think a bad coolant temperature sensor would though.

No fuel in the vacuum line. I noticed it doesn't start to blow nasty smoke until around 4,000 rpm if I slowly rev it up. Then the engine starts to swell up and down if I try to hold it there. There is still soot coming out of the tailpipe at high RPM but it is ridiculously less than before I change the two sensors.

 

[YBCold]

my haynes book says that for OBD 1

157 - Mass airflow sensor below min voltage

332 - EGR valve opening not detected

hope this helps

 

[tkarman]

my haynes book says that for OBD 1

157 - Mass airflow sensor below min voltage

332 - EGR valve opening not detected

hope this helps

Your right. I used those codes and replaced the MAF and the EGR pressure sending unit and now I have no more codes. My question involves my new problem with no codes.

 

[YBCold]

i read the rest of your question. i would say its a good idea. i might need to do the same on my x too.

 

[tkarman]

Anyone know what might be the cause of the explorer smoking and surging at 4,000 RPM?

 

[doonze]

if it's still smoking only at high RPM's maybe your getting some blow by from the rings, wouldn't be surprising on these older trucks.